Friday, April 29, 2016

A rupture disc is a one-time pressure relief device that, in most cases, protects a pressure vessel, pipe, tank, or reservoir from critical over-pressurization or damaging vacuum conditions. Rupture discs come in many sizes, materials, and mounting patterns. They are used commonly in chemical, petrochemical, pull & paper, pharmaceutical and food and beverage industries.

One unique application for rupture discs is on the hydraulic breaking system on wind turbines.

Continental Disc Corporation, a well known manufacturer of
rupture discs designed a version used for hydraulic brake systems. Their model CD31179 provides over pressure relief in an accurate and leak-free safety relief device for the control valve/accumulator system. The rupture disc assembly protects equipment from damage and down time in the event of overpressure conditions.

Continental Disk
model CD31179

Their rupture disc assembly is an efficient leak-free safety relief device for hydraulic braking systems used to stop the turbine during undesirable wind conditions and maintenance, protecting equipment from damage, and significantly reducing operating costs and downtime.

Heat transfer is the movement of heat from one body or substance to another by radiation, conduction, convection or a combination of these processes. When heating a pan of water over a gas flame for example, all three forms of heat transfer are taking place. Heat from the flame radiates in all directions. Conduction takes place with the transfer of heat from the burner to the metal pan. This heat transfer is also responsible for making the handle hot after a period of time. The water is heated by the process up convection which is a circular movement caused by heated water rising and cold water falling.

The process of heat transfer also occurs when an object cools. If a mug of hot coffee is left standing on a cold kitchen countertop its temperature will gradually decrease as heat is lost. The heat energy dissipates by conduction through the mug to the table top, by convection as the liquid rises cools, and sinks, and by the radiation of heat into the surrounding air.

One way to conserve the heat of a liquid and prevent heat transfer is to place it in a thermos. The use use of a vacuum chamber with silvered surfaces along with low conductive materials can greatly improve the amount of heat or cold that is lost to the surrounding environment.

In between the silver glass walls of a thermos lies a vacuum. In the case of a hot liquid, heat transfer by convection through the vacuum is greatly restricted due to the absence have air molecules necessary to facilitate the transfer of heat. The lack of physical contact between the inside and outside walls of the thermos due to this airless space also greatly inhibits the movement of heat by conduction.

Heat loss by radiation is prevented by the silvered walls reflecting radiant energy back into the thermos. Some conduction of heat through the stopper and glass can be expected, but this too is limited because they are made of materials with very low conductivity. Thus the temperatures of both hot and cold liquids can be maintained by a properly designed thermos that limits the transfer energy through radiation, convection, and conduction.

Heat capacity is the amount of heat required to change the temperature of an object or substance by one degree Celsius. The heat capacity of water varies depending on its phase. As solid ice, the heat capacity of water is .5 calories per gram for every one degree Celsius, which means it takes half a calorie to raise the temperature of one gram of ice one degree Celsius. As a liquid, waters heat capacity is one calorie per gram for every one degree Celsius. So it takes one calorie of heat energy to raise one gram of water one degree Celsius.

The processes a phase change between solid liquid and gas also require a specific amount of heat energy. The amount of energy required to change a liquid into a solid or a solid into a liquid is known as heat of fusion. The amount of heat required to change one gram of ice to water is 80 calories. Similarly, the heat of vaporization is the energy required to transform a liquid into a gas. It requires 540 calories to change one gram of liquid water into a gas. With these values its easy to calculate exactly how many calories of heat energy are required to transform one gram of ice, at absolute zero, to steam.

To warm 1 gram a ice from -273 degrees Celsius, to 0 degrees celsius, would be 273 times .5 gram per calorie, or about 140 calories. The phase change of one gram a ice to liquid water requires 80 calories. Then to heat the water from zero degrees Celsius to 100 degrees Celsius with the heat capacity at one calorie per gram, would require 100 calories. The final phase change of one gram of boiling water to steam would require an additional 540 calories. Adding all of these values together yields 860 calories, the amount of heat energy it takes to transform one gram of ice, at absolute zero, to steam.

Friday, April 22, 2016

The value of the content in a mixing tank in the pharmaceutical, cosmetics and food and beverage industries can be very hot. Therefore it is of utmost importance that these goods are well guarded, and the level or volume in the tank is precisely measured. Combining two or more of the following technologies provides a highly safe mixing environment.

Using guided wave radar technology, Magnetrol’s Eclipse model 705 can fulfill this requirement. This technology allows an accurate, continuous monitoring of the level or volume in the tank. An important feature of the Eclipse guided wave radar transmitter is the ability to have a probe constructed with multiple bends to conform to the exact shape of the tank. In this way, the mixing rotor placed in the middle of the tank is avoided, and the transmitter can measure to the very last drop.

Using ultrasonic technology, the Magnetrol Echotel model 961 is the ideal switch to detect a maximum high level. A significant advantage of the Echotel model 961 is its insensitivity to foam, which may develop during the mixing or blending of the liquid.

The Magnetrol Thermatel TD2 switch senses the presence or absence of liquid using thermal dispersion technology. The model TD2 can be calibrated to detect low level for things like pump protection or be used to detect flow or no flow in pipelines.

Here is a short video that illustrates the use of these level control technologies in hygienic applications.

Friday, April 15, 2016

Increased public health standards for safe drinking water and water disposition are driving the need for next generation process improvement in water and wastewater treatment plants. So are stronger environmental regulations that require responsible energy management and reuse. Level and flow instrumentation must meet these demands and provide performance, quality, and reliability.

Its extremely important to choose a vendor with an extensive line-up of instrumentation, a reputation for quality and service, and one who can deliver a single source for level flow and volume measurement applications. Every day, plant operators rely on these devices to perform accurately and reliably with their continuing mission of improving the efficiency, safety, and environmental impact on water treatment.

R82 Pulse Burst Radar

Among some of the more innovative devices available today is the Magnetrol R82 Pulse Burst Radar transmitter, an instrument that performs across a wide range of applications. The R82 is designed to provide radar reliable process measurement in challenging, vapor saturated environments at a cost that what you pay for an ultrasonic device.

For water treatment, the R82 Pulse Burst Radar transmitter provides continuous level measurement at the lift station, and coagulant feed tanks, in settling tanks during clarification, in polymer filter and lime slurry tanks during filtration, and for open atmosphere water reservoirs where the control technology must withstand punishing weather conditions.

Flow measurement plays a vital role in efficiently managing water quality processes and regulatory reporting protocol. Thermatel TA2 thermal dispersion mass flow meters offer outstanding accuracy and reliability, with the ability to maintain a strong signal at low flow rates and pressures over a wide operating flow range. The TA2 flow meters’ low flow sensitivity, wide temperature operation, and high turndown capabilities make it ideal for wastewater operations where it can manage efficient blower air flow to optimize the breakdown of waste and reduce blower costs, and it offers exceptional safety and accuracy for digester gas flow control.

Polaris Electromagnetic
Flow meter

Polaris electromagnetic flow meters monitor flow to help maintain efficient operation. Polaris flow meters have current, pulse, and alarm outputs that are configurable through the display or a DTM. Forward and reverse flow rates are measurable with the capability of empty pipe detection. Closed pipe flow control is a widespread application for the Polaris flow meter throughout water treatment plants. In wastewater treatment facilities Polaris flow meters provide efficient water and sludge flow control.

Magnetrol is a perfect example of a vendor who offers a single source solution for treatment process excellence, with controls for virtually every application, including a comprehensive line of level transmitters and switches, as well as flow meters and switches. Partnering with manufacturers like Magnetrol make the plant operators job easier by providing rugged, reliable, and high quality instrumentation designed to meet the increasing demands of today’s water storage and processing requirements.

Monday, April 11, 2016

The challenges of getting data and
control sensors inside
vacuum equipment.

Scientists and researchers are continually challenged to come up with better ways to read data inside a vacuum environment. Traditional ceramic and glass-to-metal vacuum feedthroughs don’t offer the flexibility of design required. Unique varieties of control and data signals have to pass through the wall. Not only are electrical power and control signals being passed, but fiber optic cables and pneumatic tubing may be included. Ever changing variables, such as the number and types of connectors, unique geometries, and limited available space, make it very difficult to find an off-the-shelf feedthrough. As a result, designers have traditionally been forced to make compromises and specify a feedthrough with some, but not all, of the desired specifications.

This reality has led to significant gains in custom epoxy feedthrough development. Epoxy feedthroughs overcome design restrictions. New epoxy properties have been developed that rival ceramic and glass in performance. High performance, clear epoxy potting opens the door for researchers to specify the exact number and type of wires, fiber optic cables, or any other insert they require.

Manufacturers of epoxy feedthroughs can provide a virtually limitless variety of wires, cables, or tubes along with the added benefit of fast prototyping and small production runs - perfect for the research and manufacturing community.

Prototypes with the exact number and type of have fiber-optic cables, pneumatic tubing, or run wires.

Electrical shielding is not a problem.

Epoxy feedthroughs are cost-effective.

Comply with outgassing specifications.

Allow for visual inspection when clear epoxy used.

Feedthroughs can be mounted directly to flexible circuits and printed circuit boards.

Elimination of contact resistance.

With the development of epoxy feedthroughs medical device companies, analyzer manufacturers, laboratories, aerospace companies, and other R&D facilities can design their equipment based on optimal size, cost and performance, and not be forced to compromise by ceramic and glass-to-metal feedthroughs limitations.

Because of the constant pressure on vacuum equipment researchers and OEM designers for “better, faster, smaller”, it’s clear that epoxy feedthroughs provide flexibility and options which allow for more efficient and creative design.

Tuesday, April 5, 2016

Landfill gas is a mixture of methane, carbon dioxide, and oxygen created by the action of microorganisms during decomposition within a landfill. It is made up approximately of 40% to 60% percent methane, with the remainder being primarily carbon dioxide.

Gases produced by landfills are both valuable and hazardous, and the importance of monitoring their emissions is critical. Under the Clean Air Act of 1996, many large landfills must install gas collection and control systems to collect, reuse, or flare the gas off. According to the EPA, landfills are the third largest generator of methane gas, the second most prevalent gas to contribute to the Greenhouse Gas (GHG) Effect. For that reason it is important to contain and process the methane gas in a way that it does not increase the level of GHG’s in the Earth atmosphere.

The gases produced within a landfill are readily available energy sources, and are collected and used in multiple ways. Landfill operators use a combination of wellheads, pumps, and piping to funnel these gases to a central point where they can either be burned off by a flare system or converted into renewable energy. Many landfills now see this gas as a revenue source and are now containing it and sending the gas to local power plants as renewable energy. The landfill gas can be utilized on site by a boiler or combustion system, providing heat and/or steam. Electricity can also be generated on site. Alternatively, the landfill gas can be cleaned and sold into natural gas pipelines.

Understanding this, the benefit for both a cleaner environment and a way to offset operating costs, landfill operators have much greater motivation for collecting and accurately measuring landfill gas.

Thermal mass flow meters are a proven and recognized tool in measuring the amount of flowing landfill gas, providing an accurate means of compliance with the EPA Clean Air Act, as well as for accurate production/resale measurement. Thermal mass flow meters are versatile solutions, easily calibrated to the exact gas mixture and operating temperatures that landfill operators are working under. The thermal mass flowmeter insertion probe hardware, power source, and standard 4-20 mA output makes installation easy, usually requiring just minutes to install and start-up.

The use of thermal mass flow meters, installed and measuring landfill gas flows, are now helping turn what was once waste gas into a renewable energy source.